It's winter and Tsunayoshi Sawada is forced to head to Namimori Middle and take care of I-Pin, Lambo and Futa. As they arrive at the school, Tsuna is surprised to see Hayato Gokudera, Takeshi Yamamoto, Dino and Ryohei Sasagawa waiting for them. Reborn reveals that he called them there and they volunteered to help Tsuna play with the kids. However, their idea of playing with the kids, turns out to be a snowball fight. They try to decide the teams but Reborn announces that the teams have already been decided by him: the east troop consists of Futa, Tsuna, Yamamoto and I-Pin while the west troop consists of Ryohei, Dino, Gokudera and Lambo. Gokudera is disappointed that he is not on the same team as Tsuna. However, Reborn ignores him and tells everyone the rules: the two teams have thirty minutes to fight and take Leon, who is to shapeshift as a snow ball and that anyone who loses consciousness is out.
The two teams prepare their trenches and snow balls, while Reborn puts Leon on a pillar of snow between the two teams' trenches. Reborn then declares the start of the fight. Ryohei leaves his place behind the trench and rushes in the direction of Leon, without taking a single snowball while, with his baseball abilities, Yamamoto begins to attack him with snowballs. However, Ryohei is able to destroy them with his fist. Yamamoto tries to attack with multiple snowballs, but Ryohei easily destroys them with his punches. Tsuna and Futa try to help Yamamoto by shooting more snowballs, but Ryohei easily destroys them too. As her teams throw some snowballs, I-Pin tries to get the snowball while Dino tries to stop her. However, he is unable to hit anyone since none of his subordinates are there. Gokudera then attacks her with some snowballs but she easily destroys it with her Gyoza-Kempo. However, the dumpling's extract is being carried off to the east team, making them incapable of throwing any more snowballs. With no snowballs being thrown, Ryohei tries to reach for Leon but is stopped when Gokudera knocks him unconscious with his dynamite. Gokudera switches sides, saying that his spy work is finished. Just as Gokudera leaves the west troop, Dino's men suddenly emerge from under the snow to help their boss.
However, Reborn predicted that this would happen and agrees. Saying that it's Vongola vs Cavallone, Gokudera attacks with his dynamite making the snowball fight into a fight on the snow. With his men present, Dino easily stops Gokudera's attack. Just then, Bianchi arrives and, with Lambo and I-Pin, forms a third team named Poison-Cow Chinese Cuisine.
Note: Bold + Italicized = First Appearance